And new DTrace userspace is actually under the Universal Permissive License now (which is, well, permissive). The Linux kernel module is GPL. I don't think FreeBSD needs anything from that module at all.
The UPL license also has some somewhat "unique" patent grant wording with regard to a "Larger Works" file, which can even reference external projects by name, and its supposed use as a CLA document.
Not being a lawyer (and similarly not a licensing or IP subject matter expert), and know the license was drafted by Oracle, I am somewhat suspicious of it.
And new DTrace userspace is actually under the Universal Permissive License now (which is, well, permissive). The Linux kernel module is GPL. I don't think FreeBSD needs anything from that module at all.